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<title>Decision [Enterprise Architect User Guide]</title>

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                  <p class="p_Heading1"><span class="f_Heading1">Decision</span></p>



  
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                <p class="p_TextIndentedL2"><img src="d_decision.png" width="106" height="63" border="0" alt="d_decision"></p>
<p class="p_BodyText"><span class="f_BodyText">A </span><span class="f_BodyText" style="font-style: italic;">Decision</span><span class="f_BodyText"> is an element of an <a href="activitydiagram.htm">Activity diagram</a> or <a href="interactionoverviewdiagram.htm">Interaction Overview diagram</a> that indicates a point of conditional progression: if a condition is true, then processing continues one way; if not, then another.</span></p>
<p class="p_BodyText"><span class="f_BodyText">This can also be used as a <a href="merge_node.htm">Merge node</a> in that multiple alternative flows can be merged (but not synchronized) to form one flow. The following examples show both of these modes of using the decision element.</span></p>
<p class="p_BodyText"><span class="f_BodyText" style="font-style: italic; font-weight: bold;">Used as a decision:</span></p>
<p class="p_TextIndentedL2"><img src="activity%20-%20decision.png" width="379" height="157" border="0" alt="Activity - Decision"></p>
<p class="p_BodyText"><span class="f_BodyText">See </span><span class="f_BodyText" style="font-style: italic;">UML Superstructure Specification, v2.1.1, figure 12.77, p. 363</span><span class="f_BodyText">.</span></p>
<p class="p_BodyText"><span class="f_BodyText" style="font-style: italic; font-weight: bold;">Used as a merge:</span></p>
<p class="p_TextIndentedL2"><img src="activity%20-%20merge.png" width="388" height="148" border="0" alt="Activity - Merge"></p>
<p class="p_BodyText"><span class="f_BodyText">See </span><span class="f_BodyText" style="font-style: italic;">UML Superstructure Specification, v2.1.1, figure 12.106, p. 388</span><span class="f_BodyText">.</span></p>
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<td valign="bottom" width="952" bgcolor="#efeff7" style="width:952px; background-color:#efeff7;"><p class="p_TiporNote" style="border-top: none; border-right: none; border-left: none;"><span class="f_TiporNote">Note:</span></p>
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<td width="952" bgcolor="#f7f7ff" style="width:952px; background-color:#f7f7ff;"><p class="p_TiporNoteText"><span class="f_TiporNoteText">Moving a diagram generally does not affect the location of elements in packages. If you move a diagram out of one package into another, all the elements in the diagram remain in the original package. However, Decision elements are used only within one diagram, have no meaning outside that diagram, and are never re-used in any other diagram. Therefore, if you move a diagram containing these elements, they </span><span class="f_TiporNoteText" style="font-weight: bold;">are</span><span class="f_TiporNoteText"> moved to the new parent package with the diagram.</span></p>
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<p class="p_SubHeadingL1"><span class="f_SubHeadingL1">Toolbox Icon</span></p>
<p class="p_TextIndentedL2"><img src="e_decision.png" width="172" height="22" border="0" alt="e_Decision"></p>
<p class="p_SubHeadingL1"><span class="f_SubHeadingL1">OMG UML Specification</span></p>
<p class="p_BodyText"><span class="f_BodyText">The OMG UML specification (</span><span class="f_BodyText" style="font-style: italic;">UML Superstructure Specification, v2.1.1, p. 361 (Decision symbol)</span><span class="f_BodyText">) states:</span></p>
<p class="p_OMGText"><span class="f_OMGText">A decision node is a control node that chooses between outgoing flows. A decision node has one incoming edge and multiple outgoing activity edges.</span></p>
<p class="p_BodyText"><span class="f_BodyText">The OMG UML specification (</span><span class="f_BodyText" style="font-style: italic;">UML Superstructure Specification, v2.1.1, p. 387 (Merge symbol)</span><span class="f_BodyText">) also states:</span></p>
<p class="p_OMGText"><span class="f_OMGText">A merge node is a control node that brings together multiple alternate flows. It is not used to synchronize concurrent flows but to accept one among several alternate flows... A merge node has multiple incoming edges and a single outgoing edge.</span></p>




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